Antenna



V. GRAZIANO Jan. 26, 1954 ANTENNA 2 Sheets-Sheet 1 Filed July 14, 1951INVENTOR. 61103111110 11? Mar BY 07 m imam/ Jan. 26, 1954 v. GRAZIANO2,667,577

ANTENNA Filed July 14, 1951 2 SheetsSheet 2 Patented Jan. 26, 1954ANTENNA Victor Graziano, Oak Park, Ill., assignor to Motorola, Inc.,Chicago, 111., a corporation of Illinois Application July 14, 1951,Serial No. 236,743

. 8 Claims. 1 This invention relates generally to antennas and moreparticularly to television antennas of simple construction which providehigh gain on signals in two non-contiguous frequency ranges.

Television antennas have been relatively complicated mainly becausetelevision signals have been broadcast in two non-contiguous frequencyranges in the very high frequency band. In order to provide good signalpickup, television antennas must include arms of relatively long lengthsand to provide an antenna which is suificiently rigid and which at thesame time present an attractive appearance, has resulted in structureswhich are quite expensive. Because of the very high frequenciesinvolved, it is necessary toprovide line of sight between thetransmitting and receiving antennas and accordingly it is necessary tomount the antenna at a high elevation, such as on the roof of a house.This has made the large and complicated antennas which have been usedfurther objectionable.

Although indoor antennas have been used to a considerable extent, suchantennas have provided relatively low gain and are thereforesatisfactory only in areas. having strong signals. In

many cases such antennas have required adjustment as the receiver istuned from one station to another in order to provide optimum pickup.

This is obviously objectionable. Indoor antennas or such constructiontobepositioned outside the receiver cabinet havebeen undesirable becauseor their appearance and the space required to extend the arms thereon.

I It is therefore an object of'thepresent. inventlon to provide anemcrent television antenna of simple construction.

A further object is to provide a television antenna which may beconveniently supported in an attic or the like and which provides highsignal gain.

A still further object is to provide an antenna system of veryinexpensive construction which provides high gain on both the high andlow frequency television bands.

A feature of this invention is the provision of an antenna formed byconducting layers placed on an insulating web.

A further feature of this invention is the pro visionof a bi reso'na'ntantenna system including a firstweb having thereon an antenna foroperat-lon on one frequency band, and a second web having thereon anantenna for operation on a second frequency band, with the two websbeing secured together at the en'd'sand supported in the form ofahaminock.

Another feature of this invention is the pro vision of a bi-resonantantenna system in which each antenna section is formed by an overlongdipole having the arms thereof sectionalized by condensers. The unit maybe formed by conductors placed on an insulating sheet, with thecapacitors being provided by insulating and conducting layers over theconductors at gaps therein.

Further objects and features, and the attending advantages of theinvention will be apparent from a consideration of the followingdescription when taken in connection with the accompanying drawings inwhich:

Figure 1 illustrates the antenna as installed in an attic;

Figure 2 is a top plan view of the antenna of Figure 1;

Figure 3 is a top plan view of the antenna: of Figure 1 with a portionof the top web broken away;

Figure 4 is an enlarged plan view of the, capacitor construction;

Figure 5 is a cross-section along the lines 5-4 of Figures 2 and 4;

Figure 6 illustrates the connection of a transmission line to theconductors;

Figure 7 illustrates a second embodiment of the invention;

Figure 8' shows the current distribution in the low band antenna; and,

Figure 9 illustrates the current distribution in is provided includingantenna sections operatingon the high and low band, each being anoverlong dipole with the arms thereof sectionalized by condensers. Eachantenna may be placed on a web which is supported substantiallyhorizontally, with the two webs being connected at the end so that theycan be supported as a unit. The lower web is longer than the upper webso that the lower antenna is spaced from the upper one. The web's may beof suffici'ent widththat reflectors may be provided thereon properlyspaced from the antenna elements. Alternatively, the two elements may bepositioned on a single web arranged to be positioned vertically as abanner; To increase the response in the high band, additional half-Waveelements may be connected at the ends of theoverlong dipole by phasereversing stubs.

from-the conducting strips and placing insulators and conductors:thereon. Therefore, the entire structure may be formed veryinexpensively from paper or other inexpensive web material, conductingstrips, and sections of transmission line. Connection is made directlyto the high band antenna, and to the low band antenna through a quarterwave line at the high band, with a half wave shorted stub also beingconnected across the low band antenna.

Referring now to the drawings, in Figures 1, 2 and 3 there isillustrated an antenna in accordance with the invention which is of thehammock type. In Figure 1 this antenna is shown strung up in an attic,and it is obvious that such an antenna can also be supported along awall or between any two supports. The antenna is formed by a top web orsheet I and a bottom web or sheet II which are connected together at theends, from which they are supported by cables or the like l2. Theantenna elements are formed by conducting portions on the webs which maybe provided by depositing a layer directly thereon as by sputtering orthe like, or may be provided as tape having an adhesive coating which iseasily fastened to the web.

In Figure 2 the top web is shown more in detail with conducting portionsl5, l5, l1, l8, l9 and being placed on the web I!) to form an antennaelement. The over-all length of the conducting elements is between A;wave length and one wave length at the frequencies involved. Com 1densers 2|, 22, 23 and 24 separate the various sections. Each of thesections 15, iii, !9 and 20, and the sections l1 and 18 together, areslightly less than a quarter wave length long at the highest frequencyto be received. A conducting por- 1" tion is provided at the back of thestrip which is approximately one-half wave length long and serves as areflector for the antenna to thereby increase the gain in the usualmanner. Connection to the antenna is made at the junction of sections l1and 18 by a section of transmission line 26, and a shortage stub 21 isalso connected to the junction for a reason to be explained more indetail hereinafter.

The antenna provided on the top web 10 is for reception on the lowtelevision band extending through the range from 54 megacycles to 88megacycles, and to provide proper response in this range, the sectionsI5 and l6, l9 and 20 are each approximately inches long, and thesections I1 and 18 are each approximately 15 inches long. The capacitors21, 22, 23 and 24 are each of the order of ten micromicrofarads. Thereflector 25 is approximately ninety five inches long and is spaced fromthe antenna by about 44 inches.

As shown in Figures and 5, these condensers are formed by cutting a slotin the web and conductor and providing insulating and conducting layersthereacross. Figures 4 and 5 illustrate the condenser coupling theportions 18 and 19, with the adjacent antenna portions. This may also bean adhesive conducting layer which may be easily applied, or aconducting layer deposited directly on the insulating layer 3|.

In Figure 3, in which the top web is broken away, the high band antennasection is shown more in detail. As previously stated, this is providedon a web I I longer than the web It so that it hangs below the web Illand is thereby spaced therefrom. The antenna is formed by conductingportions 35, 36, 31, 38, 39 and 40 which form an overlong dipole in thehigh frequency band in generally the same manner as the antenna for thelow frequency band. The various sections are separated by condensers 4|,42, 43 and 44 which may be constructed in the manner shown in Figures 4and 5 previously described.

For operation in this frequency band, which extends from 174 to 216megacycles, the sections 35, 35, 39 and 40 are of the order of 10 incheslong and the sections 31 and 3B are each 5 inches long. The gain in thehigh band can be increased by the use of reflectors 45, and by theaddition of half wave dipole elements connected to the ends of the unitsas indicated at 46 and 41. These elements are connected to the ends ofthe overlong dipole by shorted quarter wave stubs 48 and 49. Tin'eereflectors are used, each being 30 inches long and spaced from the highband antenna section by 16 inches. The elements 48 and 41 are of theorder of 27 inches long and the stubs 48 and 49 may be formed bysections of 300 ohm transmission lines 12 inches long.

Referring again to Figure 1 it is seen that the transmission line 26connects the low band antenna on the web It) directly to the high bandantenna on the web ll. Connection to the entire unit then is made by atransmission line 50 connected to the high band antenna. Figure 6illustrates the maner in which connection of the transmission lines maybe made to the conducting portions of the antenna. By making the line 25of a length equal to a quarter wave on the high band, and by the use ofthe shorted half wave stub 21, the low band antenna is completelyisolated from the high band antenna. When operating with the frequenciespreviously referred to, the transmission line 28 may be a 300 ohm line12 inches long, and the stub 21 may be a 300 ohm line 24 inches long. Onthe low band, the shorted stub 21 and the high band antenna are bothhigh impedances and therefore have substantially no effect on theoperation of the low band antenna.

Figures 8 and 9 show the current distribution in the antenna sectionsfor the two bands. The antenna system as shown has provided substantialgain over tuned half-wave dipoles with the system showing a gain in thelow band of 1.7 to 1 without a reflector and 2.4 to 1 with a reflector,and a gain in the high band of 1.4 to 1 without a reflector and 2.5 to 1with a reflector.

In Figure 7 there is illustrated a simplified embodiment wherein the twoantenna elements are provided on a single web arranged to be supportedvertically as a banner. This web has the low band antenna 56 at the topthereof, and the high band antenna 51 at the bottom. The antennaelements themselves may be exactly identical to those shown in Figures 1to 3 inclusive with the two antennas being spaced vertically insubstantially the same manner. The antennas 56 and 51 are connected by atransmission line 58, and a shorted stub 55! is connected to the antenna56. The signals picked up in the antennas may be applied to a receiverthrough the transmission line 55 connected to the high band antenna 51.

It is apparent from the foregoing that the antenna system of theinvention may be constructed very simply and inexpensively from readil'yavailable materials. The structure is made up of insugees-aw iating maypaper b15131, db'hdlltihg stiips thereon tvlfih may her d8- po'siife diiilefly on the-Web O'r applied thlto by 'adhesive. The-capacitersconnecting the sections are-simply provided by insulating layersbridging adjacent "ends of the conducting elements, and other conductingstrips over theinsulating layers 'to'form'condensers which connecttheinterrupted portions of the strips. The'stubs'requiredm'a'yb'eprovided-simplyfrom-3'00 ohm transmission line such asis used for thelead in from the antenna so "that the very few differentmaterials "arerequired anda'very simpleassembly 'process thereof ispossible.

The'a'ntenna is of such "configuration "that "it can" be easilyinstalled'ina spaces'uch as a n'attic having limited head room. Th'eover-all length 'dfthe unit is of the order of 12- feetso thatsuiii'cient room'woul'a be availablein the attic of most houses. Aspreviously pointed ousnewever, the antenna is not limited toinstallation in attics but may be installed between any two supports,and may be so constructed that it is suitable for outside installations.

Although certain embodiments of the invention have been described whichare illustrative thereof, it is obvious that various changes andmodifications may be made therein without departing from the intendedscope of the invention as defined in the appended claims.

I claim:

1. An antenna system for receiving wide hand signals in twonon-contiguous frequency ranges including in combination, Web meansformed of insulating material, conducting portions on said web meansforming first and second dipole antennas for individually receivingsignals in said two frequency ranges, each of said dipole antennashaving two opposed arms each including a plurality of spaced conductingportions and conducting means spaced from adjacent conducting portionsforming condensers which interconnect said adjacent conducting portions,each of said arms having a length greater than one-half Wave length andless than one wave length of the highest frequency to be receivedthereby, each of said conducting portions having a length less thanone-quarter wave length of the highest frequency to be received thereby,and means interconnecting said antennas and including terminals forreceiving signals picked up by said antenna system.

2. An antenna system for receiving wide band signals in twonon-contiguous frequency ranges including in combination, web meansformed of insulating means, conducting portions on said web meansforming first and second dipole antennas I for individually receivingsignals in the higher and lower of said frequency ranges respectively,each of said dipole antennas having two opposed arms each including aplurality of spaced conducting portions and capacitors interconnectingthe same,

each of said antennas havin a length greater than one-half Wave lengthand less than one wave length of the highest frequency to be receivedthereby, each of said conducting portions having a wave length less thanone-quarter wave length of the highest frequency to be received thereby,a pair of additional conducting portions having a length substantiallyequal to one-half a wave length in said high frequency range extendingfrom said opposed arms of said first antenna, stubs having a lengthsubstantially equal to a quarter wave length in said high frequencyrange connecting said additional conducting portions to 6 "said arms ofsaid first antennaf-a'nd ineaiis fritr connecting said antennas andincluding "termirials "for receiving signals picked up by said an--tenna system.

"3. An "antenna system for receivingtele'vision signals including incombinatioma web of insulating material, a conducting layer on said webincluding portions forming a dipole antenna, "s'aid dipole antennahaving two'opposed arms each including a plurality of spaced conductingportions and conducting means spaced from adjacent conductin porticnsforming capacitors whichc'o'nnect said adjacent conducting portions,said "airtenn'a having a length greaterthanone halfwave length and lessthan one wave length of theliighest frequency to be received thereby,each of said conducting portions having a wave length less thanone-quarter wave length of the highest frequehcyto be received thereby,iadditidhalbdiidiikftin g portions having a length substantiallyequal'tb one-half wave length extending from said opposed arms, andquarter wave stubs connecting said additional conducting portions tosaid arms.

4. An antenna system for receiving television signals in two widenon-contiguous frequency ranges, including in combination, a firstelongated web of insulating material having conducting portions thereonforming a first antenna and a first reflector for the lower frequencyrange, a second elongated web of insulating material having conductingportions thereon forming a second antenna and a second reflector for thehigher frequency range, each of said antennas including a plurality ofspaced elongated portions and conductor means providing condenser meansinterconnecting said spaced portions, said web being secured together atthe ends thereof, with one of said webs being longer than the other andsaid shorter web being positioned above said longer web, and meansinterconnecting said first and second antennas.

5. An antenna system for receiving television signals in two widenon-contiguous frequency ranges, including in combination, a firstelongated web of insulating material having conducting material thereonforming an antenna and a reflector for the lower frequency range, asecond elongated web of insulating material having conducting materialthereon forming an antenna and a reflector for the higher frequencyrange, said webs being secured together at the ends thereof, with one ofsaid webs being longer than the other and said longer web beingpositioned below said shorter web so that the center portion thereof isspaced from said shorter web, and means interconnecting said antennas onsaid first and second webs and isolating the same from each other sothat each of said antennas has substantially no effect on the other inthe frequency range thereof, said interconnecting means including singleterminal means for providing signals from said antennas on both saidfirst and second webs.

6. An antenna system in accordance with claim 1 wherein said web meansincludes a first web for supporting said first dipole antenna and asecond web for supporting said second dipole antenna, said first andsecond webs being secured together at the end thereof with one of saidwebs being longer than the other, said webs being supported in agenerally horizontal position with said longer web being below saidshorter web so that the center portions of said webs are spaced fromeach other.

7. An antenna system in accordance with claim 14 1 wherein said webmeans includes a sheet positioned generally vertical with said dipoleantennas positioned generall horizontally thereon, one above the other.

8. An antenna system for receiving wide band signals in twonon-contiguous frequency ranges including in combination, a firstelongated Web of insulating material having thereon a plurality ofelectrically interconnected conducting portions forming a first dipoleantenna for operation in the lower frequency range, a second elongatedweb of insulating material having thereon a plurality of electricallyinterconnected conducting portions forming a second dipole antenna foroperation in the higher frequency range, said webs being securedtogether at the ends thereof with one of said webs being longer than theother, said webs being positioned generally horizontal with said longerweb below said shorter web so that the center portion thereof is spacedvertically from said shorter web, and means electrically interconnectingsaid antennas on said first and second webs and substantiallyelectrically isolating the same from each other so that each of saidantennas has substantially no effect on the other in the frequencyranges thereof, said interconnected means including single terminalmeans for providing signals from said first and second antennas on saidfirst and second webs.

VICTOR GRAZIANO.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,039,988 Graves May 6, 1936 2,101,033 Mashbir et al. Dec. 7,1937 2,248,800 Alford July 8, 1941 2,474,480 Kearse June 28, 19492,485,482 Cork Oct. 18, 1949

